Registration Number
0218U001451,
0115U000638
, R & D reports
Title
Influence of defect structure on voiding, lattice flow and on phase competition during interdiffusion
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Head
Gusak Andriy, Доктор фізико-математичних наук
Registration Date
09-02-2018
Organization
B. Khmelnitsky state university in Cherkasy
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The influence of pre-treatment of copper substrate on the quantity, size and spatial distribution of pores occurring in the phase layer of Cu3Sn during the solid-phase reaction of copper with tin or with the Cu6Sn5 phase was experimentally investigated. The comparison is made for copper substrates after prolonged annealing, after rolling of different degrees, for substrates, applied by a galvanic method with different current densities. The distribution of pores along the interface deviates from Poisson's one. The formation of local accumulation of pores indicates the influence of the orientation of individual grains on the nucleation of pores. The competing factors influencing the porosity in the Cu3Sn phase during copper and solder reaction are the average grain size and dislocation density. Increase of the defect density of the substrate leads to a larger total number of pores, but, on the other hand, the percentage of pores pinned by the mobile interface Cu3Sn / Cu, decreases. The kinetic model was first created, which explains this property by the so-called kinetic pining of pores in the gradient field of the concentration of vacancies near the interface. The model of the second type of porosity induced by the external flow induced by the lamellar spongy structure of Cu3Sn + pores was induced. The model allows for predicting the rate of formation of the structure and the characteristic dimensions of the lamellar structures through thermodynamic driving forces and coefficients of interphase and surface diffusion of tin. Molecular dynamics applied to the nickel-aluminum interaction, predicts the dependence of the reaction kinetics and the sequence of phase formation on the conditions of film deposition. Formation of liquid channels between the grains of the Cu6Sn5 phase as the main mechanism of mass transfer in the reaction of copper with a liquid solder has been proved unambiguously, ending 15 years of discussions. Voiding in copper-tin reactions can be overcome if one suppresses the growth of the Cu3Sn, in which the pores usually occur. The conditions for the suppression by the Cu6Sn5 of lateral expansion of the Cu3Sn phase were first found. A computer model of intermediate phase competition in the SHS reactions in multi-layer foils with partial heat dissipation was developed. The dependence of the shape of the temperature profile on the front of the SHS on the sequence of phase transformations and the morphology of the reaction zone is found. In sufficiently thin films, the reaction itself can proceed without the formation and competition of intermediate compounds, but by dissolving nickel in liquid aluminum to the formation of a stoichiometric composition followed by crystallization. The new method for atomistic modeling - Stochastic Kinetic Mean-Field (SKMF) - is suggested.
Product Description
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Безпальчук Володимир Миколайович
Запорожець Тетяна Василівна
Король Ярослав Дмитрович
Ляшенко Олексій Юрійович
Ляшенко Юрій Олексійович
Марченко Станіслав Віталійович
Пасічний Микола Олександрович
Сторожук(Тютюнник) Надія Вікторівна
Сущенко Ігор Віталійович
Турло Владислав Васильович
Тютенко Василь Михайлович
Царенко Максим Васильович
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2020-04-02
